1. Field of the Invention
The present invention concerns safety guards and retrofitting of safety guards to medical needles.
2. Description of the Relevant Art
Accidental needle stick injuries are common among health care workers such as doctors, nurses, laboratory personnel and housekeeping personnel. Accidental needle sticks with contaminated needles can result in the transmission of those diseases which ar transmissible through the blood. The severe health hazards and consequences associated with these diseases have resulted in well-thought-out protocols for handling medical needles and a near universal use of needle and syringe disposal containers.
Notwithstanding the care taken with contaminated medical needles, it is estimated in the publication Bio-Medical International, Vol. IX. 23-24 for December, 1986 that "an estimated 800,000 sharp or needle sticks occur each year in the U.S.". It is further estimated that "primary treatment (gamma globulin, hepatitis B immune globulin, tetanus) and subsequent blood analysis and care costs . . . $600-$1,000 per incident". This figure may be compared with a similar report that "each needle stick injury cost a hospital more than $200.00" as stated in U.S. Pat. No. 4,592,744. Whatsoever the actual stick injury, it is indisputable that each such injury is psychologically disconcerting to the health care worker receiving the injury.
Accidental needle sticks most often occur when a drawer of blood, or any administrator injecting a patient, attempts to recap or dispose of a needle, syringe or vacuum tube phlebotomy system after use. Although modern health care protocols seldom allow for any prolonged exposure of a contaminated needle upon a work surface, in some instances a contaminated needle is set upon a work surface by one person, normally the administrator, and is subsequently removed for disposal by another person, normally an assistant or nurse. During the course of this handling and interchange accidental self-sticks and sticks of other persons occasionally occur.
Although prior art needle guards and sheaths have been developed to help prevent accidental needle sticks, such prior art guards have been incompatible with, i.e. incapable of being fitted to, the various differing style existing medical needles and syringes. In this regard, Bio-Medical International estimates the size of the total U.S. disposable medical needle syringe market to be approximately $260,000,000. Of this total market, approximately $132,000,000 is in the hospital segment. In this segment market leaders such Becton-Dickinson and Sherwood each possess an approximate 45 percent market share. In the physican and consumer market segment, estimated at $73,000,000, Becton-Dickinson enjoys an approximate 70 percent market share. Finally, in the specialty market segment of approximate $55,000,000 Becton-Dickinson possesses an approximate 30 percent market share. while Sherwood possesses an approximate 20 percent market share. From these statistics it is obvious that any guard for a medical needle needs to be compatible with, i.e. retrofitable to, the various differing leading needle and syringe designs of manufacturers such as Becton- Dickinson and Sherwood.
If the fitting or the retrofitting of safety guards or sheaths to preexisting medical needles and/or syringes is to be contemplated, then certain properties of these medical needles and/or syringes should be considered. The tips of medical needles or syringes are extremely sharp, and should not be dulled by contact with any other surfaces prior to their use in medical injection. Medical needles and syringes are delivered into use in sterile condition, and must be maintained or reestablished in this condition after the fitting or retrofitting of any sheath thereon. Medical needles and syringes are preferably disposable, dictating that any retrofitted sheath should additionally be disposable. Particularly, such a sheath should be of low cost and should be no more environmentally hazardous than are the spent needles and syringes themselves.
In order to reliably and invariably perform its function, a guard or sheath should be permanently affixed to the medical needle and/or syringe which it protects. Despite variations in the physical structure of such needles and/or syringes, it would be useful if a protective sheath, nonetheless to the requiredment that it should be permanently affixed, were to be of universal application among and between the various prior art differing needles and syringes.